/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification of Java bytecode.
 *
 * Copyright (c) 2002-2018 GuardSquare NV
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.classfile.editor;

import proguard.classfile.attribute.*;
import proguard.util.ArrayUtil;

/**
 * This class can add exceptions to the exception table of a given code attribute. The exceptions must have been filled
 * out beforehand.
 *
 * @author Eric Lafortune
 */
public class ExceptionInfoEditor {
    private final CodeAttribute codeAttribute;

    /**
     * Creates a new ExceptionInfoEditor that can add exceptions to the given code attribute.
     */
    public ExceptionInfoEditor(CodeAttribute codeAttribute) {
        this.codeAttribute = codeAttribute;
    }

    /**
     * Prepends the given exception to the exception table.
     */
    void prependException(ExceptionInfo exceptionInfo) {
        ExceptionInfo[] exceptionTable = codeAttribute.exceptionTable;
        int exceptionTableLength = codeAttribute.u2exceptionTableLength;

        int newExceptionTableLength = exceptionTableLength + 1;

        // Is the exception table large enough?
        if (exceptionTable.length < newExceptionTableLength) {
            ExceptionInfo[] newExceptionTable = new ExceptionInfo[newExceptionTableLength];

            System.arraycopy(exceptionTable, 0, newExceptionTable, 1, exceptionTableLength);
            newExceptionTable[0] = exceptionInfo;

            codeAttribute.exceptionTable = newExceptionTable;
        } else {
            System.arraycopy(exceptionTable, 0, exceptionTable, 1, exceptionTableLength);
            exceptionTable[0] = exceptionInfo;
        }

        codeAttribute.u2exceptionTableLength = newExceptionTableLength;
    }

    /**
     * Appends the given exception to the exception table.
     */
    void appendException(ExceptionInfo exceptionInfo) {
        codeAttribute.exceptionTable =
            ArrayUtil.add(codeAttribute.exceptionTable, codeAttribute.u2exceptionTableLength++, exceptionInfo);
    }
}